Induction of protective immunity against antigens

Abstract

Described herein are compositions and methods for making and using recombinant bacteria that are capable of regulated attenuation and/or regulated expression of one or more antigens of interest.

What is claimed is: 
     
       1. A recombinant derivative of a pathogenic bacterium, wherein the bacterium is a  Salmonella enterica , and wherein the bacterium comprises
 a murA gene operably linked to a first sugar-regulatable promoter, wherein the first sugar-regulatable promoter is an arabinose-regulatable promoter, a rhamnose-regulatable promoter, or a xylose regulatable-promoter; 
 a deletion-insertion mutation that inactivates the expression of asdA gene and inserts a c2 gene; 
 a deletion in a pmi gene; 
 a deletion in a pagL gene; 
 a waaL gene operably linked to a second sugar-regulatable promoter, wherein the second sugar-regulatable promoter is an arabinose-regulatable promoter, a rhamnose-regulatable promoter, or a xylose regulatable-promoter; 
 a deletion in a wza-wcaM gene; 
 a deletion-insertion mutation that inactivates the expression of a RelA gene and inserts a lacI gene; 
 a deletion in a recF gene; and 
 a deletion in a sifA gene. 
 
     
     
       2. The bacterium of  claim 1 , wherein the first sugar-regulatable promoter is selected from the group consisting of araC P araBAD , rhaRS-P rhaBAD  and xylR-P xylA . 
     
     
       3. The bacterium of  claim 2 , wherein the second sugar-regulatable promoter is selected from the group consisting of araC P araBAD , rhaRS-P rhaBAD  and xylR-P xylA . 
     
     
       4. The bacterium of  claim 3 , wherein
 the deletion-insertion mutation that inactivates the expression of the asdA gene and inserts the c2 gene is ΔasdA27::TT araC PBA D c2; 
 the deletion in the pmi gene is Δpmi-2426; 
 the deletion in the wza-wcaM gene is Δ(wza-wcaM)-8; 
 the deletion-insertion mutation that inactivates the expression of the RelA gene and inserts the locI gene is ΔrelA197::araC PBA D locI TT; 
 the deletion in the recF gene is ΔrecF126; and 
 the deletion in the sifA gene is ΔsifA26. 
 
     
     
       5. The bacterium of  claim 1 , wherein the bacterium further comprises a gene encoding an antigen of interest operably linked to a third sugar-regulatable promoter. 
     
     
       6. The bacterium of  claim 5 , wherein the third sugar-regulatable promoter is a lactose-regulatable promoter. 
     
     
       7. The bacterium of  claim 6 , wherein the lactose-regulatable promoter is P trc . 
     
     
       8. The bacterium of  claim 5 , wherein the antigen of interest is an antigen derived from an infectious agent or a cancer antigen. 
     
     
       9. The bacterium of  claim 6 , wherein the antigen is a  Clostridium perfringens  antigen. 
     
     
       10. The bacterium of  claim 9 , wherein the  Clostridium perfringens  antigen is a NetB antigen or antigenic fragment thereof, a PlcC antigen or antigenic fragment thereof, or a fusion protein comprising the NetB antigen or antigenic fragment thereof and the PlcC antigen or antigenic fragment thereof. 
     
     
       11. The recombinant bacterium of  claim 10 , wherein the bacterium comprises the plasmid pYA5112. 
     
     
       12. A pharmaceutical composition comprising the recombinant bacterium of  claim 1 , and a pharmaceutically acceptable carrier. 
     
     
       13. A method for eliciting an immune response against an antigen of interest in a subject, the method comprising administering to the subject an effective amount of a pharmaceutical composition of  claim 12 . 
     
     
       14. The method of  claim 13 , wherein the subject has necrotic enteritis. 
     
     
       15. The method of  claim 13 , wherein the subject is a chicken. 
     
     
       16. The method of  claim 13 , wherein the pharmaceutical composition is administered to the subject by spray or oral immunization.